growth and ageing Flashcards
growth can involve 2 cellular changes, what are these?
- increase in cell numbers (hyperplasia)
- increase in cell size (hypertrophy)
which cells cannot regenerate?
neurons
growth can be affected by which 2 factors?
- genetic
- environmental
humans have 2 main growth phases, when are these?
- birth
- around 12
name hormones that influence growth
- thyroid hormone
- growth hormones
- sex hormones
- insulin
- cortisol
- parathyroid hormone
thyroid hormone is essential for normal growth and development, what role does it play?
- essential fro protein synthesis in foetal/infant brain
- required for normal development of neurons
- necessary for childhood growth
- facilitate action of growth hormone and sympathetic nervous system
what effect might hypothyroidism have on a growing child?
- impede brain and skeletal growth
- delayed tooth eruption
- growth defects
what re the metabolic actions of growth hormone?
- increase blood glucose
- decrease glucose uptake by cells
- increased lipolysis (make fatty acids available)
- facilitate uptake of amino acids for proteins synthesis
- cartilage/bone/soft tissue/viscera growth
describe hypothyroid dwarfism
- missing thyroid hormone
- infant proportions
describe hypopituitary dwarfism
- missing growth hormone
- normal proportions
which 2 hormones are responsible for the pubertal growth spurt?
oestrogen and testosterone
the effects of oestrogen and testosterone are mediated by an increase in which 2 hormones?
GH and IGF-1
what effects do oestrogen and progesterone have on bone growth?
- stimulate bone growth
- accelerate closure of epiphyseal growth plates
describe the anabolic effect of testosterone
-effect on protein synthesis increasing muscle bulk
insulin has no direct effect on growth, how does it contribute indirectly?
- promote foetal growth
- promote post-natal growth by stimulating IGF-1
- facilitate protein synthesis
